Sentrin Specific Protease 3 (SENP3)

SENP3 and SENP5 colocalized with nucleophosmin (NPM1), a protein involved in ribosome biogenesis, within the granular component of the nucleolus. Codepletion of SENP3 and SENP5 in HeLa cells via RNA interference (RNAi), but not depletion of either SENP alone, increased the nucleolar content of SUMO1, SUMO2, and SUMO3. Depletion of SENP3 alone inhibited production of 28S rRNA from the 32S precursor RNA, whereas depletion of SENP5 alone reduced 47S transcription. RNAi-mediated depletion of nucleophosmin reduced SENP3 and SENP5 levels, likely via increased degradation rather than decreased expression. Codepletion of SENP3 and SENP5 or depletion of nucleophosmin resulted in accumulation of sumoylated RPL37A and GNL2 proteins within nucleoli.